Can Polyherbal Medicine be used for the Treatment of Diabetes? - A Review of Historical Classics, Research Evidence and Current Prevention Programs

Diabetes mellitus (DM), a chronic medical condition, has attained a global pandemic status over the last few decades affecting millions of people. Despite a variety of synthetic drugs available in the market, the use of herbal medicines for managing diabetes is gaining importance because of being comparatively safer. This article reviews the result of a substantial literature search on polyherbal formulations (PHFs) developed and evaluated with potential for DM. The accumulated data in the literature allowed us to enlist 76PHFs consisting of different parts of 147 plant species belonging to 58 botanical families. The documented plant species are laden with bioactive components with anti-diabetic properties and thus draw attention. The most favoured ingredient for PHFs was leaves of Gymnema sylvestre and seeds of Trigonella foenum-graecum used in 27 and 22 formulations, respectively. Apart from herbs, shilajit (exudates from high mountain rocks) formed an important component of 9 PHFs, whereas calcined Mytilus margaritiferus and goat pancreas were used in Dolabi, the most commonly used tablet form of PHF in Indian markets. The healing properties of PHFs against diabetes have been examined in both pre-clinical studies and clinical trials. However, the mechanism(s) of action of PHFs are still unclear and considered the pitfalls inherent in understanding the benefits of PHFs. From the information available based on experimental systems, it could be concluded that plant-derived medicines will have a considerable role to play in the control of diabetes provided the challenges related to their bioavailability, bioefficacy, optimal dose, lack of characterization, ambiguous mechanism of action, and clinical efficiency are addressed.

Anthocyanins' effects on diabetes mellitus and islet transplantation

The incidence of diabetes mellitus is dramatically increasing every year, causing a huge global burden. Moreover, existing anti-diabetic drugs inevitably bring adverse reactions, and the application of islet transplantation is often limited by the damage caused by oxidative stress after transplantation. Thus, new approaches are needed to combat the growing burden of diabetes mellitus. Anthocyanins are of great nutritional interest and have been documented that have beneficial effects on chronic diseases, including diabetes mellitus. Here, we describe the health effects of anthocyanins on diabetes mellitus and islet transplantation. Epidemiological studies demonstrated that moderate intake of anthocyanins leading to a reduction in risk of diabetes mellitus. Numerous experiments both animal and clinical studies also showed positive effects of anthocyanins on prevention and treatment of diabetes and diabetic complications. These effects of anthocyanins may be related to mechanisms of improving glucose and lipid metabolism and insulin resistance, antioxidant, and anti-inflammatory activities. In addition, damage and function of pancreatic islets after transplantation are also improved by anthocyanins. These findings suggest that daily intake of anthocyanins may not only improve nutritional metabolism in healthy individuals to prevent from diabetes, but also as a supplementary treatment of diabetes mellitus and islet transplantation. Thus, more evidence is needed to better understand the potential health benefits of anthocyanins.

Effects of anthocyanin supplementation in diet on glycemic and related cardiovascular biomarkers in patients with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials

Purpose

This study is the first systematic review and meta-analysis based on RCTs on the effects of anthocyanins on patients with type 2 diabetes mellitus (T2DM) and the effect on T2DM-related cardiovascular disease.

Methods

RCTs published in English from five electronic databases were evaluated for glycated hemoglobin (HbA1c), fasting blood glucose (FBG), 2-h postprandial blood glucose, fasting insulin, model assessment for insulin resistance, triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, systolic blood pressure, and diastolic blood pressure. The quality of the studies was rated (Cochrane Risk of Bias tool) and weighted mean differences were calculated (DerSimonian-Laird model with random effects). Leave-one-out sensitivity, subgroup, and publication bias analyses were conducted. The strength of the evidence was rated according to the GRADE guidelines.

Results

In all, 13 RCTs were analyzed out of the 239 identified studies, with a duration longer than 4 weeks (703 participants with T2DM). Our findings indicate that a median dose of 320 mg/day anthocyanins, either from fruit extracts or pure supplements, for a median intervention length of 8 weeks significantly reduced HbA1c [Weighted Mean Difference (WMD) -0.31, p = 0.00], FBG (WMD -0.63, p = 0.00), 2-h postprandial glucose (WMD -1.60, p = 0.00), TG (WMD -0.45, p = 0.01), and LDL (WMD -0.26 p = 0.02). However, the effects of anthocyanins on fasting insulin, HOMA-IR, TC, HDL cholesterol, systolic blood pressure, and diastolic blood pressure in patients with T2DM were not statistically significant. Anthocyanins from fruit extracts or powder exhibited a higher reduction of HbA1c compared to pure anthocyanin supplements.

Conclusion

The significant improvements in glycemic parameters and lipid profile, suggest the benefits of anthocyanins, especially from fruit extract or powder, in the management of T2DM, and their ability to delay the onset of lipid disorder-related diseases such as cardiovascular disease associated with T2DM. The mechanism behind this reduction in glycemic markers could be attributed to the antioxidant and anti-inflammatory activity of anthocyanins. Further research with well-designed RCTs is required to determine the optimal dosage of anthocyanins for the treatment of T2DM and to comprehend the consequences.

How effective are anthocyanins on healthy modification of cardiometabolic risk factors: a systematic review and meta-analysis

BACKGROUND

In this meta-analysis, findings from recent studies on the preventive properties of anthocyanins (ACN) against cardiovascular disease are summarized.

METHODS

MEDLINE, PubMed, Embase, Cochrane Library, and Google Scholar were searched and 2512 studies were found in a preliminary search. After screening of titles and abstracts, 47 studies met the inclusion criteria (randomized clinical trial design and sufficient data of outcomes). Studies were excluded based on the following criteria: incomplete data; obscurely reported outcomes, or lack of control groups; and animal studies.

RESULTS

The results showed that intervention with ACNs resulted in a significant decrease in body mass index ((MD),- 0.21; 95% CI, - 0.38, - 0.04; P < 0.001) and body fat mass (MD: - 0.3%, 95% CI - 0.42 to - 0.18%, p < 0.001). Pooled data comparing ACN with control showed statistically significant effect on fasting blood sugar and HbA1c. However, the reductions were significantly more in the subjects with type 2 diabetes and in those who used ACN as supplement/extract. The subgroup analysis test showed that there was a significant effect of ACN on triglyceride concentrations, total cholesterol, LDL-C and HDL-C concentrations in all subgroups of participants (with vs. without dyslipidemia at baseline) and intervention type (supplement/extract vs. food). However, we did not observe any significant effect on apo A and apo B concentrations.

CONCLUSIONS

ACN intake in the forms of natural foods and supplements can induce healthy changes in body fat mass, glycemic and lipidemic status and these effects are more prominent in the subjects with above-normal values. This meta-analysis was registered at http://www.crd.york.ac.uk/Prospero (Registration no. CRD42021286466).

Food Polyphenols and Type II Diabetes Mellitus: Pharmacology and Mechanisms

Type II diabetes mellitus and its related complications are growing public health problems. Many natural products present in our diet, including polyphenols, can be used in treating and managing type II diabetes mellitus and different diseases, owing to their numerous biological properties. Anthocyanins, flavonols, stilbenes, curcuminoids, hesperidin, hesperetin, naringenin, and phenolic acids are common polyphenols found in blueberries, chokeberries, sea-buckthorn, mulberries, turmeric, citrus fruits, and cereals. These compounds exhibit antidiabetic effects through different pathways. Accordingly, this review presents an overview of the most recent developments in using food polyphenols for managing and treating type II diabetes mellitus, along with various mechanisms. In addition, the present work summarizes the literature about the anti-diabetic effect of food polyphenols and evaluates their potential as complementary or alternative medicines to treat type II diabetes mellitus. Results obtained from this survey show that anthocyanins, flavonols, stilbenes, curcuminoids, and phenolic acids can manage diabetes mellitus by protecting pancreatic β-cells against glucose toxicity, promoting β-cell proliferation, reducing β-cell apoptosis, and inhibiting α-glucosidases or α-amylase. In addition, these phenolic compounds exhibit antioxidant anti-inflammatory activities, modulate carbohydrate and lipid metabolism, optimize oxidative stress, reduce insulin resistance, and stimulate the pancreas to secrete insulin. They also activate insulin signaling and inhibit digestive enzymes, regulate intestinal microbiota, improve adipose tissue metabolism, inhibit glucose absorption, and inhibit the formation of advanced glycation end products. However, insufficient data are available on the effective mechanisms necessary to manage diabetes.

Effects of blueberry and cranberry on type 2 diabetes parameters in individuals with or without diabetes: A systematic review and meta-analysis of randomized clinical trials

AIMS

Blueberry and cranberry are rich in polyphenols that are associated with diabetes reduction. This study aimed: 1) to systematically review the literature on the effects of blueberry and cranberry consumption and type 2 diabetes parameters in individuals with or without type 2 diabetes and 2) to quantify these effects by carrying out a meta-analysis.

DATA SYNTHESIS

A systematic review and meta-analysis were performed using articles present in seven databases (PubMed, LILACS, Scielo, Scopus, Web of Science, Cochrane, and Embase), including publications until May 2021. We included randomized clinical trials that compared blueberry or cranberry effects on type 2 diabetes parameters, such as fasting blood glucose, insulin resistance, and glycated hemoglobin. Quality of the studies was performed using the Cochrane scale, while the Egger test assessed the publication bias and meta-regression the estimated effect sizes with potential moderator variables. From the 2034 studies identified, 39 were read in full and 22 were included in meta-analysis. In individuals with diabetes, the consumption of blueberry or cranberry significantly reduced fasting blood glucose [MD: -17.72 mg/dl; 95% CI: -29.62, -5.82; p = 0.03; I2 = 57%] and glycated hemoglobin [MD: -0.32%; 95% CI: -0.57, -0.07; p = 0.15; I2 = 39%], whereas for insulin resistance the effects were null. Results were not significant for the general population, except in the sensitivity analysis for fasting blood glucose.

CONCLUSIONS

The consumption of blueberry and cranberry significantly reduced fasting blood glucose and glycated hemoglobin levels in individuals with diabetes, with high credibility of the evidence.

Hypoglycemic bioactivity of anthocyanins: A review on proposed targets and potential signaling pathways

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated interrelationships responsible for initiating its pathogenesis. Novel strategies for the treatment of this devastating disease have attracted increasing attention worldwide. Anthocyanins are bioactive compounds that are widely distributed in the plant kingdom, and multiple studies have elucidated their beneficial role in preventing and managing T2DM. This review summarizes and comments on the hypoglycemic actions of anthocyanins from the perspective of molecular mechanisms and different target-related signaling pathways in vitro, in vivo, and clinical trials. Anthocyanins can ameliorate T2DM by functioning as carbohydrate digestive enzyme inhibitors, facilitating glucose transporter 4 (GLUT4) translocation, suppressing the effectiveness of dipeptidyl peptidase IV (DPP-IV), promoting glucagon-like peptide-1 (GLP-1) secretion, inhibiting protein tyrosine phosphatase 1B (PTP1B) overexpression, and interacting with sodium-glucose co-transporter (SGLT) to delay glucose absorption in various organs and tissues. In summary, anthocyanin is a promising and practical small molecule that can hyperglycemic symptoms and accompanying complications suffered by patients with diabetes. However, rational and potent doses for daily intake and clinical studies are required in the future.

Efficacy of flavonoids on biomarkers of type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials

A systematic review and meta-analysis of 28 randomized controlled trials (RCTs) to assess the efficacy of flavonoids intake on key biomarkers related to Type 2 diabetes mellitus was conducted. The mean difference (MD) with 95% confidence intervals (95% CI) was pooled using a random-effects model. Significant reduction in fasting glucose (MD: -0.22, 95% CI: -0.34 to -0.09, p = 0.0013), hemoglobin A1c (HbA1c) (MD: -0.26, 95% CI: -0.46 to -0.05, p = 0.021), homeostasis model assessment of insulin resistance (HOMA-IR) (MD: -0.40, 95% CI: -0.66 to -0.15, p = 0.0039), triglyceride (TG) (MD: -0.13, 95% CI: -0.21 to -0.05, p = 0.002), total cholesterol (TC) (MD: -0.14, 95% CI: -0.21 to -0.08, p = 0.0002), and low density lipoprotein-C (LDL-C) (MD: -0.15; 95% CI: -0.24 to -0.07, p = 0.0009) were observed in intervention group compare to placebo at the end of trial. Moreover, flavonoid intake had negative but non-significant effect on insulin (MD: -0.46), 2 h-postprandial glucose (2 h-PPG) (MD: -0.22), homeostasis model assessment of β-cell function (HOMA-β) (MD: -2.81), and insignificantly increased high-density lipoprotein-C (HDL-C) (MD: 0.03). In conclusion, flavonoid intake has modest but statistically significant benefits in glucose metabolism, insulin sensitivity, and lipid metabolism, especially for significantly lowing fasting blood glucose, HOMA-IR, HbA1c, TG, TC, and LDL-C.

The effect of anthocyanins supplementation on liver enzymes among patients with metabolic disorders: A systematic review and meta-analysis of randomized clinical trials

The present study aims to summarize and quantitatively examine the available evidence on the effectiveness of anthocyanin supplementation on liver enzymes among patients with metabolic disorders, by employing a systematic review and meta-analytic approach. Online databases including PubMed/Medline, Scopus, ISI Web of Science, and Cochrane Library were searched up to June 2020 for randomized controlled trials (RCTs) that examined the effect of anthocyanin supplementation on serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) among patients with metabolic disorders. To estimate the overall effect of anthocyanin supplementation, we employed the random-effects model. In total, 12 RCTs were included in the systematic review. Pooled analysis did not show any significant changes in ALT (WMD: -0.92 U/L, 95% CI: -4.19 to 2.35, p = .58; I²  = 91.3%) and AST (WMD: -1.22 U/L, 95% CI: -3.43 to 0.99, p = .28; I²  = 87.0) concentrations after supplementation with anthocyanin. The dose and duration of supplementation were the potential sources of heterogeneity among most of the trials. However, subgroup analysis showed that the effect is not statistically significant in all subgroups. Overall, in our study, anthocyanin does not have any effect on liver enzyme levels significantly. However, future high-quality studies are still needed to confirm the results.

The effect of (Cornus mas L.) fruit extract on liver function among patients with nonalcoholic fatty liver: A double-blind randomized clinical trial

This double-blind randomized clinical trial aimed to investigate impact of Cornus mas L. fruit extract (CMFE) on liver function in nonalcoholic fatty liver disease (NAFLD). Fifty patients were randomly assigned into the CMFE and placebo groups to receive 20 ml of the extract or placebo for 12 weeks, respectively. Serum alanine aminotransferase, aspartate aminotransferase, cytokeratin 18 (CK-18) levels, and steatosis and fibrosis scores were examined before and after the intervention. Although, a significant decrease was observed in CK-18 levels among the CMFE group (288.80 ± 85.40 vs. 235.66 ± 60.38; p = .001) after 12 weeks, no significant difference was found between the two groups. Moreover, a significant increase in fibrosis score in the placebo group (8.20 (6.35-9.40) vs. 8.40 (7.70-13.00); p = .03) as well as a significant difference in this marker (CMEF: 7.64 (6.30-8.25); placebo: 8.40 (7.70-13.00); p = .02) and its changes (CMEF: 0.60 (-1.00-1.07); placebo: 0.80 (-0.25-3.95); p = .02) were found between the groups after 12 weeks. No significant effect was noted on other variables. Therefore, consuming CMFE might have some beneficial effects on liver function markers in NAFLD. However, more studies are required in this area.

Alpha-amylase as molecular target for treatment of diabetes mellitus: A comprehensive review

The alpha (α)-amylase is a calcium metalloenzyme that aids digestion by breaking down polysaccharide molecules into smaller ones such as glucose and maltose. In addition, the enzyme causes postprandial hyperglycaemia and blood glucose levels to rise. α-Amylase is a well-known therapeutic target for the treatment and maintenance of postprandial blood glucose elevations. Various enzymatic inhibitors, such as acarbose, miglitol and voglibose, have been found to be effective in targeting this enzyme, prompting researchers to express an interest in developing potent alpha-amylase inhibitor molecules. The review mainly focused on designing different derivatives of drug molecules such as benzofuran hydrazone, indole hydrazone, spiroindolone, benzotriazoles, 1,3-diaryl-3-(arylamino) propan-1-one, oxadiazole and flavonoids along with their target-receptor interactions, IC₅₀ values and other biological activities.

The effect of anthocyanins supplementation on liver enzymes: A systematic review and meta-analysis of randomized clinical trials

This systematic review and meta-analysis aimed to assess effect of consuming anthocyanins (ACNs; pure ACNs or products containing ACNs) on liver enzymes levels including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT). Although no significant impact was detected on the liver enzymes, a significant reduction was observed on ALT (WMD = -4.932 U/L, 95% CI = -9.848 to -0.015, p = .049) and AST (WMD = -3.464 U/L, 95% CI = -6.034 to -0.894, p = .008) in the studies that examined them as primary outcomes. A significant decrease was found on AST among the healthy subjects (WMD = -4.325 U/L, 95% CI = -8.516 to -0.134, p = .043) and in the studies that used products containing ACNs as intervention (WMD = -2.201 U/L, 95% CI = -4.275 to -0.127, p = .037). Although no significant relation was detected between ACNs dosage and the liver enzymes, significant associations were found between the duration of trial with ALT (ALT: slope: 0.09, 95% CI = 0.040 to 0.139, p = .0003) and AST (slope: 0.076, 95% CI = 0.037 to 0.115, p = .0001). In conclusion, although ACNs had no significant effect on the liver enzymes, a significant decrease was discovered on ALT and AST in the studies that evaluated them as primary outcomes. A significant reduction was observed in AST in the healthy individuals and in the studies used products containing ACNs as intervention. Significant relations were also found between the duration of trial with ALT and AST. Further studies are required to confirm these results.

Antidiabetic potential of dietary polyphenols: A mechanistic review

Diabetes is a metabolic disorder that has caused enormous harm to the public health worldwide. In this study, we evaluated the potential of phenolic compounds on diabetes management, addressing their mechanisms of action, in addition to discussing the digestion, absorption, metabolism, bioavailability, and toxic effects of these compounds. The intake of phenolic compounds can play a fundamental role on diabetes management, since they can reduce blood glucose levels, oxidative stress, protein glycation, inhibit the activity of dipeptidyl peptidase - IV and other key enzymes related to carbohydrate metabolism, activate various biochemical pathways to improve pancreatic β-cell functions, increase insulin secretion, and improve insulin resistance. In this way, they can be considered a potential strategy in the development of pharmaceutical approaches that aim to reduce complications resulting from the progression of this metabolic pathology.

Identification of phenolic compounds in fruits of Ribes stenocarpum Maxim. By UHPLC-QTOF/MS and their hypoglycemic effects in vitro and in vivo

The gooseberry (Ribes stenocarpum Maxim. (CBZ)) is a wild and noncommercially cultivated berry fruit widely distributed in the Tibetan Plateau. The phenolic constituents from the berry fruit of CBZ were firstly identified by employing UPLC-QTOF MS. A total of 41 compounds, including hydroxycinnamic acids, hydroxybenzoic acids, flavonols and dihydroflavonol, were identified in view of their molecular weight, characteristic fragment ions and retention times. Further in vitro enzyme assay indicated that CBZ fruit extract could strongly and effectively inhibited a-glucosidase and α-amylase, with the IC₅₀ values of 0.013 mg/mL and 0.005 mg/mL, respectively. In addition, the starch/maltose/sucrose tolerance experiment demonstrated that the CBZ fruit extract could reduce the sucrose mediated postprandial blood glucose (PBG) levels in normal mice, and significantly lower starch/maltose/ sucrose mediated PBG levels in diabetic mice. These results suggested that this berry fruit could be used as a dietary supplement, or drug for the control of hyperglycemia.

Effect of Berry Polyphenols on Glucose Metabolism: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The effect of berry polyphenols on glucose metabolism has been evaluated in several studies; however, the results are conflicting. A systematic review and meta-analysis was therefore conducted to evaluate the effect of berry polyphenol consumption on glucose metabolism in adults with impaired glucose tolerance or insulin resistance. PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, CINAHL (EBSCO), and Scopus were searched for randomized controlled trials published by June 2019. Of the 3240 articles found, 21 met inclusion criteria. Study-specific effects were calculated as mean differences, which were pooled using fixed-effect, inverse-variance weighting. Overall, berry polyphenol consumption did not have a clear effect on biomarkers of glucose metabolism compared with placebo or no treatment. Although some analyses showed statistically significant effects, these effects were too small to be of clinical relevance. The review protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews as CRD42019130811.

The role of anthocyanins as antidiabetic agents: from molecular mechanisms to in vivo and human studies

Diabetes mellitus is a chronic metabolic disease characterized by high blood glucose concentration. Nowadays, type 2 diabetes or insulin resistant diabetes is the most common diabetes, mainly due to unhealthy lifestyle. Healthy habits like appropriate nutritional approaches or the consumption of certain natural products or food supplements have been suggested as non-pharmacological strategies for the treatment and prevention of type 2 diabetes. Some of the main bioactive compounds from plant foods are polyphenols, important mainly for their antioxidant capacity in oxidative stress conditions and ageing. Anthocyanins are polyphenols of the flavonoid group, which act as pigments in plants, especially in fruits such as berries. A search of in vitro, in vivo and human studies in relation with antidiabetic properties of anthocyanins has been performed in different electronic databases. Results of this review demonstrate that these compounds have the ability to inhibit different enzymes as well as to influence gene expression and metabolic pathways of glucose, such as AMPK, being able to modulate diabetes and other associated disorders, as hyperlipidaemia, overweight, obesity and cardiovascular diseases. Additionally, human interventional studies have shown that high doses of anthocyanins have potential in the prevention or treatment of type 2 diabetes; nevertheless, anthocyanins used in these studies should be standardized and quantified in order to make general conclusions about its use and to claim benefits for the human population.

Effect of dietary anthocyanins on biomarkers of glycemic control and glucose metabolism: A systematic review and meta-analysis of randomized clinical trials

Anthocyanins, as natural food colorants, are bioactive substances with several health advantages. In this research, the effects of dietary anthocyanins on biomarkers of glycemic control and glucose metabolism was evaluated through a meta-analysis. The results revealed a significant reduction in levels of fasting blood sugar (FBS; -2.70 mg/dl, 95% CI: -4.70 to -1.31; P < 0.001), 2-h postprandial glucose (2-h PPG; -11.1 mg/dl, 95% CI: -18.7 to -3.48; P = 0.004), glycated hemoglobin (HbA1c; -11.1 mg/dl, 95% CI: -18.7 to -3.48; P = 0.004), homeostasis model assessment of insulin resistance (HOMA-IR; -0.54, 95% CI: -0.94 to -0.14; P = 0.008), resistin (-1.23 µg/l, 95% CI: -2.40 to -0.05; P = 0.041), and plasminogen activator inhibitor-1 (PAI-1; -5.09 µg/l, 95% CI: -9.45 to -0.73; P = 0.022) following administration of anthocyanins, whilst changes in the levels of fasting insulin (0.33 mU/l, 95% CI: -0.18 to 0.85; P = 0.207) and C-peptide (-0.02 µg/l, 95 %CI: -0.20 to 0.16; P = 0.816) was not statistically significant. Consumption of anthocyanins for >8 weeks and at doses >300 mg/day significantly reduced levels of FBS, 2-h PPG, HbA1c, and HOMA-IR. Moreover, anthocyanins administration reduced the levels of FBS, 2-h PPG, HbA1c, and HOMA-IR in type 2 diabetic subjects and HOMA-IR in overweight/obese individuals. Overall, dietary anthocyanins can be used as an adjuvant therapy to improve biomarkers of glycemic control and glucose metabolism specially in diabetic subjects.

Efficacy and Safety of a Traditional Herbal Combination in Patients with Type II Diabetes Mellitus: A Randomized Controlled Trial

BACKGROUND

Capparis spinosa, Rosa canina, Securidaca securigera, Silybum marianum, Urtica dioica, Trigonella foenum-graecum and Vaccinium arctostaphylos are used traditionally as an herbal combination for treatment of diabetic patients in Iran. Despite the clinical evidence supporting their use in solitary form, no controlled human study has determined the efficacy and safety of their combination in treatment of diabetic patients.

METHODS

A total 150 type II diabetic patients of both sexes under the oral anti-hyperglycemic drugs treatment (maximum 10 mg glyburide and 1000 mg metformin daily) were randomly assigned to three groups. The patients in each group received either herbal combination or placebo or metformin capsule daily for three months, without any change in their previous oral anti-hyperglycemic drugs dosage. Herbal combination, placebo and metformin capsules matched by shape and color were prepared in the Institute of Medicinal Plants Karaj, Iran. To assess the efficacy and safety of the treatments, the patients fasting plasma glucose, HbA1c, lipid profile, liver enzymes and renal function were determined at the beginning of the study and after three months.

RESULTS

Results showed that after three months, the fasting plasma glucose, HbA1c and cholesterol levels in herbal combination were decreased significantly as compared to placebo group (20% and 12% respectively) and also compared to base line (25% and 15% respectively). The herbal combination was as effective as metformin in reduction of FPG (p = 0.001, p = 0.001) and HbA1c (p = 0.028 and p = 0.050 respectively) compared to placebo. No notable hepatic, renal and gastrointestinal side effects were observed in the trial groups.

CONCLUSION

The results suggest that traditional herbal combination may safely improve glycemic control in type II diabetic patients with no significant adverse effect. [Formula: see text].

A facile ultrasonic-aided biosynthesis of ZnO nanoparticles using Vaccinium arctostaphylos L. leaf extract and its antidiabetic, antibacterial, and oxidative activity evaluation

The synthesis of nanoparticles often result in the generation of harmful chemical pollutants. As such, many researchers have focused on developing green processes, which include the biosynthesis. In this research, ZnO nanoparticles were prepared using the leaf extract of whortleberry (Vaccinium arctostaphylos L.) via a simple ultrasonic-assisted method. The morphology, crystal size and structure, surface, thermal, and optical properties of the bio-mediated ZnO sample (ZnO_ext) were analyzed and compared with that produced without incorporating the extract (ZnO_chem). The ZnO samples were evaluated for their antidiabetic, antibacterial, as well as their sono- and photo-catalytic performances. Initially, the samples were intraperitoneal injected to alloxan-diabetic rats to examine their treatment efficiency in terms of effects on fasting blood glucose, insulin, cholesterol, high-density lipoprotein, and total triglyceride levels. The ZnO_ext showed significantly higher efficiency for improving the health status of alloxan-diabetic rats in contrast with other tested treatments, vis. ZnO_chem, insulin, and only leaf extract. In addition, both the ZnO samples were assessed against gram-negative and gram-positive bacteria and through sono- and photo-catalytic processes for removing rhodamine B, respectively. The results of this study indicated that not only the ZnO_ext sample was pollution free, it also exhibited higher potentials for treating diabetic rats, bacterial decontamination, and also oxidative removal of organic compounds under the influences of ultrasound and UV irradiations when compared with ZnO_chem sample.

Antihypertensive efficacy and safety of Vaccinium arctostaphylos berry extract in overweight/obese hypertensive patients: A randomized, double-blind and placebo-controlled clinical trial

OBJECTIVES

To evaluate the antihypertensive efficacy and safety of a standardized Vaccinium arctostaphylos (V. arctostaphylos) berry hydro-alcoholic extract in the overweight/obese hypertensive patients.

DESIGN

Randomized placebo-controlled trial.

SETTING

Baqiyatallah hospital (Tehran, Iran).

INTERVENTIONS

The antihypertensive efficacy and safety of 3-month intake of 400 mg extract capsule three times daily alongside standardized anti-hypertensive regimen in the treatment of 50 patients was compared with the placebo (n = 50).

MAIN OUTCOME MEASURES

SBP (systolic blood pressure), DBP (diastolic blood pressure), body mass index, waist circumference, CBC (complete blood count), blood levels of AST (aspartate aminotransferase), ALT (alanine aminotransferase), ALP (alkaline phosphatase), BUN (blood urea nitrogen) and creatinine.

RESULTS

SBP decreased from 152.1 ± 7.7 to 140.5 ± 10.7 in the V. arctostaphylos group and from 152.9 ± 8.1 to 150.8 ± 9.3 in the placebo group (P < 0.001). DBP decreased from 90.3±8 to 82.1±8.8 in the V. arctostaphylos group and from 89.6 ± 7.8 to 87.6 ± 7.9 in the placebo group (P < 0.001). The extract capsule had no significant effect on the other parameters (P > 0.05). Moreover, no drug side effect and adverse interaction with other antihypertensive drugs was observed in the patients.

CONCLUSIONS

V. arctostaphylosberry extract improves blood pressure control and has safety and tolerability in the overweight/obese hypertensive patients taking standard antihypertensive drugs.

Meta-Analysis of the Effects of Foods and Derived Products Containing Ellagitannins and Anthocyanins on Cardiometabolic Biomarkers: Analysis of Factors Influencing Variability of the Individual Responses

Understanding interindividual variability in response to dietary polyphenols remains essential to elucidate their effects on cardiometabolic disease development. A meta-analysis of 128 randomized clinical trials was conducted to investigate the effects of berries and red grapes/wine as sources of anthocyanins and of nuts and pomegranate as sources of ellagitannins on a range of cardiometabolic risk biomarkers. The potential influence of various demographic and lifestyle factors on the variability in the response to these products were explored. Both anthocyanin- and ellagitannin-containing products reduced total-cholesterol with nuts and berries yielding more significant effects than pomegranate and grapes. Blood pressure was significantly reduced by the two main sources of anthocyanins, berries and red grapes/wine, whereas waist circumference, LDL-cholesterol, triglycerides, and glucose were most significantly lowered by the ellagitannin-products, particularly nuts. Additionally, we found an indication of a small increase in HDL-cholesterol most significant with nuts and, in flow-mediated dilation by nuts and berries. Most of these effects were detected in obese/overweight people but we found limited or non-evidence in normoweight individuals or of the influence of sex or smoking status. The effects of other factors, i.e., habitual diet, health status or country where the study was conducted, were inconsistent and require further investigation.

Effects of blueberry and cranberry consumption on type 2 diabetes glycemic control: A systematic review

The metabolic effects of cranberry and blueberry consumption on glycemic control have been evaluated in vitro and in animal models as well as in human studies, although findings have not been systematically reviewed yet. Therefore, a systematic review was carried out of relevant randomized clinical trials (RCTs) in order to assess the effect of berries (blueberry and cranberry) consumption on type 2 diabetes (T2DM) glycemic control. Some evidences were also discussed on the anti-diabetic mechanisms exerted by berries polyphenols. Studies were identified by searching electronic databases: LILACS, PubMed/MEDLINE, Scopus, The Cochrane Library and Web of Science. Three authors independently searched and extracted RCTs in which the effect of berries (cranberry or blueberry) consumption on T2DM glycemic control was assessed. A total of 7 RCTs, involving 270 adults with type 2 diabetes were included. Despite the heterogeneity of the administration forms (in natura, dried, extract, preparations - juice), dosage, duration of the intervention and type of population of the studies involving these two berries some studies highlight the potential benefit of berries, especially of blueberry, on glucose metabolism in T2DM subjects. Daily cranberry juice (240 mL) consumption for 12 weeks and blueberry extract or powder supplementation (9.1 to 9.8 mg of anthocyanins, respectively) for 8 to 12 weeks showed a beneficial effect on glucose control in T2DM subjects. Those results indicate a promising use of these berries in T2DM management; although more studies are required to better understand the mechanisms involved.

Role of Purified Anthocyanins in Improving Cardiometabolic Risk Factors in Chinese Men and Women with Prediabetes or Early Untreated Diabetes-A Randomized Controlled Trial

Objective: In vitro and animal studies suggest that purified anthocyanins have favorable effects on metabolic profiles, but clinical trials have reported inconsistent findings. Furthermore, no study has been specifically conducted among individuals with prediabetes. The aim of this study was to investigate whether purified anthocyanins could improve cardiometabolic risk factors in Chinese adults with early untreated hyperglycemia. Research Design and Methods: This was a 12-week randomized, double-blind, placebo-controlled trial. A total of 160 participants aged 40–75 years with prediabetes or early untreated diabetes were randomly allocated to receive either purified anthocyanins (320 mg/day, n = 80) or placebo (n = 80) of identical appearance. A three-hour oral glucose tolerance test (OGTT) was performed, and cardiometabolic biomarkers (glycated hemoglobin A1c (HbA1c), fasting and postprandial glucose, insulin, C-peptide, and lipids) were measured at baseline and at the end of the trial. Results: A total of 138 subjects completed the protocol. Compared with placebo, purified anthocyanins moderately reduced HbA1c (−0.14%, 95% CI: −0.23~−0.04%; p = 0.005), low-density lipoprotein-c (LDL-c) (−0.2 mmol/L, 95% CI: −0.38~−0.01, p = 0.04), apolipoprotein A-1 (apo A1) (0.09 g/L, 95% CI: 0.02~0.17; p = 0.02), and apolipoprotein B (apo B) (−0.07 g/L, 95% CI: −0.13~−0.01; p = 0.01) according to intention-to-treat analysis. Subgroup analyses suggested that purified anthocyanins were more effective at improving glycemic control, insulin sensitivity, and lipids among patients with elevated metabolic markers. Conclusions: The 12-week randomized controlled trials (RCT) in Chinese adults with prediabetes or early untreated diabetes indicated that purified anthocyanins favorably affected glycemic control and lipid profile. Future studies of a longer duration that explore the dose-response relationship among patients with cardiometabolic disorders are needed to confirm our findings.

Effects of Anthocyanins on Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Numerous clinical trials have examined the role of anthocyanins on cardiometabolic health, but their effects have not been quantitatively synthesized and systematically evaluated. The aim of our study was to conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the effects of anthocyanins on glycemic regulation and lipid profiles in both healthy populations and those with cardiometabolic diseases. The MEDLINE, EMBASE, Cochrane database, OVID EBM Reviews, and clinicaltrials.gov databases were searched until February 2017. RCTs with a duration of ≥2 wk that evaluated the effects of anthocyanins on glycemic control, insulin sensitivity, and lipids as either primary or secondary outcomes were included. The Cochrane Risk of Bias tool was used to assess the study quality. Standardized mean differences (SMDs) were determined by random-effects models. Meta-regression, sensitivity, and subgroup analyses were performed to explore the influence of covariates on the overall effects. Thirty-two RCTs (1491 participants) were eligible for meta-analysis. Anthocyanins significantly reduced fasting glucose (SMD: -0.31; 95% CI: -0.59, -0.04; I² = 80.7%), 2-h postprandial glucose (SMD: -0.82; 95% CI: -1.49, -0.15; I² = 77.7), glycated hemoglobin (SMD: -0.65; 95% CI: -1.00, -0.29; I² = 72.7%), total cholesterol (SMD: -0.33; 95% CI: -0.62, -0.03; I² = 86.9%), and LDL (SMD: -0.35; 95% CI: -0.66, -0.05; I² = 85.2%). Sensitivity analyses showed that the overall effects remained similar by excluding the trials with a high or unclear risk of bias. The significant improvements in glycemic control and lipids support the benefits of anthocyanins in the prevention and management of cardiometabolic disease. Further well-designed RCTs are needed to evaluate the long-term effects of anthocyanins on metabolic profiles and to explore the optimal formula and dosage. The protocol for this review was registered at https://www.crd.york.ac.uk/PROSPERO/#index.php as CRD42016033210.

Controlling type 2 diabetes mellitus with herbal medicines: A triple-blind randomized clinical trial of efficacy and safety

BACKGROUND

The use of alternative medicines is common in patients with diabetes mellitus. The primary aim of the present study was to determine the effects of cinnamon and Caucasian whortleberry (Vaccinium arctostaphylos L.) on blood glucose control, lipid profile and body mass index (BMI) in patients with type 2 diabetes (T2DM).

METHODS

In all, 105 T2DM patients were recruited to the present randomized triple-blinded clinical trial. Patients were randomly divided into three groups and administered either placebo, cinnamon or whortleberry supplements (1 g/day) for 90 days. Fasting blood glucose (FBG), serum insulin, lipid profiles, and HbA1c were measured before and after the study.

RESULTS

There were no significant differences in baseline characteristics among the three groups. After treatment, FBG, 2-h blood postprandial glucose and homeostasis model assessment of insulin resistance (HOMA-IR) scores were significantly reduced in patients in the whortleberry group, but not in the placebo group. After treatment, there was a significant difference in BMI between the cinnamon and control groups (P = 0.02). There were no significant differences in any variables between the cinnamon and whortleberry groups (P>0.05 for all). In addition, there was a significant decrease in all indices of glucose control in all the cinnamon and whortleberry groups (P < 0.05).

CONCLUSIONS

There were no significant differences in blood glucose levels, insulin sensitivity or lipid profile among the three groups. However, the use of cinnamon and whortleberry in addition to conventional medical treatment is recommended to adjust weight and blood glucose levels in patients with T2DM, respectively.

Ethnopharmacological knowledge of Shiraz and Fasa in Fars region of Iran for diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

This study provides ethnopharmacological knowledge of traditional herbal healers from Shiraz and Fasa in Fars region (Iran) for treatment of diabetes mellitus.

MATERIALS AND METHODS

Field surveys were carried out during September 2013-February 2014 in Shiraz and Fasa. The data were collected through structured questionnaire in Persian. All plant species recorded for the treatment of diabetes mellitus were sampled. Samples were identified by a botanist and obtained a voucher specimens number and deposited in the Shiraz School of Pharmacy Herbarium. The information such as scientific name, family, local name, medicinal use(s), parts used and preparation method were provided. Literature review on available data about antidiabetic effect of the addressed plant species was done to highlight gaps in current knowledge and propose the next steps.

RESULTS

In total, 50 informants were interviewed. Totally 39 plant species were recommended by herbal healers, of which 28 are native to Iran. The most recommended plants for diabetes were Trigonella foenum-graecam (28 Attars), Securigera securidaca (22 Attars), Vaccinium arctostaphylos (18 Attars). The most abundant families were Fabaceae, Asteraceae, Lamiaceae and Apiaceae. Plant parts used were mainly seeds, flowers, leaves and fruits. The most usual preparation methods were decoction, powder and distillation. Around 44% of all reported plants for diabetes are also in use for obesity management

CONCLUSIONS

This study provided ethnopharmacological knowledge from Fars region in Iran for a specific disease and we have introduced important plant species which are recommended by local herbal healers for diabetes mellitus. For 23% of reported plants, clinical studies approved antidiabetic properties and for 61%, animal studies approved antidiabetic activity.

Trends in publication of evidence-based Traditional Iranian medicine in endocrinology and metabolic disorders

Traditional Iranian medicine (TIM) is a main part of complementary and alternative medicine (CAM). The popularity and use of alternative therapies are increasing due to adverse effects and ineffectiveness of pharmacologic treatments in some cases. Herbal medicine is one of the methods of traditional therapy that plays a key role in the treatment of various diseases specifically in diabetes mellitus, hyperlipidemia and obesity that are growing rapidly in the world. In this article, trends of scientific publications of Iranian medicine in endocrinology and metabolic disorders have been investigated. Our data show that the numbers of related researches have uptrend from 2000 till now. These data are valuable to pharmaceutical companies to get the idea to invest and produce effective drugs.